Difference between revisions of "Neutron pinball"

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==The Simulation==
 
==The Simulation==
Photons with a Bremsstrahlung energy distribution are incident upon 64 thorium cylindrical targets. All thorium targets have 1 cm center-to-center spacing, a dia. of 0.4 cm, and a height of 8 cm. The target geometry is shown the neutron flux plot below. Photofission neutrons were simulated using the MCNPX ACE model.  Upon the creation of a neutron, its initial direction of travel is logged and compared with the direction of travel as seen by a detector placed 150 cm away from the target. The target is surrounded by a cylindrical volume of air with a radius of 150cm and a height equal to the vertical extent of the detectors (76cm).
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Photons with a Bremsstrahlung energy distribution are incident upon 64 thorium cylindrical targets. All thorium targets have 1 cm center-to-center spacing, a dia. of 0.4 cm, and a height of 8 cm. The target geometry is shown in the neutron flux plot below. The targets are surrounded by a cylindrical room filled with air, which is given a radius equal to the distance between the target and the detectors (150 cm), and a height equal to the vertical extent of the detectors (76 cm). .  Upon the creation of a neutron, its initial direction of travel is logged and compared with the direction of travel as seen by a detector placed 150 cm away from the target. The detector determines direction of travel by physical location,
  
[[File:Neutronflux.png|400 px|thumb|center|Prompt neutron flux from photofission in thorium cylinders. Photons are traveling from left to right.]]
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[[File:Neutronflux.png|400 px|thumb|center|A uniform plane source of Bremsstrahlung photons,traveling from left to right, induce induce photofission. The rate of neutron production is represented by the color. ]]
  
 
==Results==
 
==Results==

Revision as of 01:09, 30 January 2016

The Simulation

Photons with a Bremsstrahlung energy distribution are incident upon 64 thorium cylindrical targets. All thorium targets have 1 cm center-to-center spacing, a dia. of 0.4 cm, and a height of 8 cm. The target geometry is shown in the neutron flux plot below. The targets are surrounded by a cylindrical room filled with air, which is given a radius equal to the distance between the target and the detectors (150 cm), and a height equal to the vertical extent of the detectors (76 cm). . Upon the creation of a neutron, its initial direction of travel is logged and compared with the direction of travel as seen by a detector placed 150 cm away from the target. The detector determines direction of travel by physical location,

A uniform plane source of Bremsstrahlung photons,traveling from left to right, induce induce photofission. The rate of neutron production is represented by the color.

Results

14.5% of neutrons scattered in the thorium cylinders alone, and 16.5% scattered when air was included. The histogram below shows that if a neutron did scatter, it most likely did so at an unacceptable angle.


Non-zero deflection angles of neutrons


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